PLANT AND ANIMAL ASSOCIATIONS 59 



a flock of gulls which were feeding on the sands. Their 

 excreta proved to consist of well-defined heaps of white, 

 pale pink, and dark shells. The white proved to consist 

 of barnacles, the pink of " henpens " {Macoma)^ and the 

 dark heaps of mussels comminuted. All the heaps were 

 practically pure, showing that the birds had confined them- 

 selves to one type of food at a time. Finally, a monkey, the 

 Crab-Eating Macaque {Macacus cynomolgus)^ derives its name 

 from its habit of feeding on crabs from the brackish waters 

 of the lagoons and swamps of the Malayan coast. 



